Adjustable diaphragm



Nov. 19, 1940. H. NERWlN ADJUSTABLE DIAPHRAGM Filed Sept. 27, 1939 A l 4 MM Patented Nov". 19, 1940 UNITED vSTATES ADJUSTABLE DIAPHRAGM Hubert Nei-win, Dresden,

Aktiengesellschaft, Dresden, Ger- Zeiss Ikon many Germany, assignor to Application September 27, 1939, Serial No. 296,803 In YGermany November 18, 1938 3 Claims. (Cl. 95-64) The invention relates to improvements in adjustable diaphragms for photographic objectives and particularly is directed to diaphragms used in. photographic objectives of mirror reflex 5 camera or cameras provided with a mirror reilex inder attachment.

In mirror reflex cameras the photographic obduringvthe adjustment. venient but requires much 30 sult that the versatility of paired. l

It is the object of the present invention to overcome s is not only inconthe camera. is im- .2, however, with time, with the rement ofthe diaphragm when the diaphragm adjusting member is moved toward diaphragm` closing position. 1

Other objects of the invention will be apparent or will be specifically pointed out in the dej scription forming a part of this speciiication, but the invention is not limited to the embodiment of the invention herein described, as various forms may be adopted within the scope of the claims. i g l Referring to the figures which illustrate by way of example one embodiment of the invention:

Fig. 1 is an elevation view, partly in section of a `photographic objective moimt provided 15 with the novel adjustable diaphragm of the present invention.

Fig.. 2 is a cross-sectional view, with parts broken away, substantially along the line II-II of Figs. 1 and 4. 1;

Fig. 3 is a cross-sectional view similar to Fig. the locking ring in anothe.`

position, and Figs. 4 and 5 are 'sectional views substantially along the; lines IV-IV and V-V respectively 25 adjusting ring l isprovided at the lower edge a0 outer circumference of the axial 45 shown in Figs. 1 and 5. The outerI end of the strip I3 has 'an operating button I5 attached thereto. The lower edge of the flange 5 is provided with a series of notches I6, I'I, I8 and I9, 60 I each of which representing one diaphragm aperture and each of which being adapted to receive selectively the outwardly extended portion of the resilient strip I3. -When the button I5 is depressed in the direction of the arrow in Fig. 5 U

Vnumeral 8 appea v notch I8 and then` the resilient strip I3 is released from the notch of the flange i and now a relative rotation between the diaphragm adjusting ring 4 and the locking ring i is'possible and the strip Il may be moved in engagement with anyv other one o! the notches Il to Il.'

The outer circumference of the locking ring 8 is provided with a diaphragm aperture scale 20 corresponding to the customary diaphragm scale 22 on the diaphragm adjusting ring 4. The ilange 5 of the diaphragm adjusting ring 4 is p rovided with a window opening 23 in which ap-V pears one numeral o! the scale 20 one at a time to indicate to what smallest aperture the diaphragm I may be adjusted when the diaphragm adjusting ring 4 is rotated in diaphragm closing direction, which in Figs. 2 and Bis in clockwise direction.

In the drawing (Figs. 1 and 2) the diaphragm aperture has been adjusted to its largest a`perture 1:4. The resilient strip I3 engages the notch Il and the pin I0 engages the shoulder 21 formed by one end of the arcuate recess I2 in the member l. It is apparent Ithat the diaphragm adjusting ring 4 cannot be adjusted unless the locking ring 8 is unlatched from the diaphragm adjusting ring 4, l by actuating the button I5 to bring the resilient strip I3 out of engagement with the notch I6. phragm the aperture and exposing the nlm.

If it is desired to expose the nlm with a smaller aperture, for instance 1:8, then the button I5 is actuated to move the resilient strip I3 out of the the diaphragm adjusting ring 4, 5 is rotated relatively to the ring 6 until the rs in the w 2l. The thus locking the ring adjusting ring 4, B but engages the notch I8 1:4 is used for focusing button I5 is now released, I again to the diaphragm at this time the strip Il (Fig. 4). It is now possible to rotate the dia- Phragm ring 4, 5 between the apertures 1:8 and 1:4. When focusing it wil be of advantage to employ the larger aperture 1:4.'which can be readily adjusted by rotating the ring 4, 5 anticlockwise until a stop yis telt, namely, when the diaphragm is fully open. Before making the exposure the diaphragm adjusting rotated clockwise until another stopis felt, namely when the pin In engages the shoulder 21. A glance at the window. will indicate that the diaphragm has been adjusted to the previously selected aperture 1:8. o

What I claim isti 1. In an adjus able diaphragm for. photographic objectives, a manually rotatable diaphragm adjusting ring providedat one end with a series of circumferentially spaced notches, a second ring within said diaphragm adjusting ring and independently rotatable with respect to the latter, a manually controlled leaf spring attached to said second ring for selectively engaging any the aperture jection onsaid second'ring when the diaphragm adjusting ring is rotated in a direction in which of the diaphragm is reduced, where- In this position 0f the dia` ring 4, 5 is again by the reduction in the size of the diaphragm aperture is limited to the Vsise represented by the selected position in which said second ring is locked to said diaphragm adjusting ring, and means for indicating the diaphragm aperture to which the diaphragm is adjustable when said` ing means comprising a scaleon the outer circumference of ring and a window in that portion of the dia- Phragm adjusting ring covering the outer circumference of said second ring.

2. In an adiustable diaphragm graphic objectives, a -manually rotatable diaphragm adjusting ring, a second ring diaphragm adjusting ring and independently rotatable with respect to the latter, manually controled means for locking said tively in a series of adjusting ring, said manually controlled means including a resilient strip attached with one end to said second ring and resiliently engaging said diaphragm adjusting ring with its-other end, said last named end ted to engage selectively provided in said diaphragm adjusting ring, each of said notches representing' a termined diaphragmv aperture, said second ring, and a stationary member on which said second ring is rotatably mounted, said stationary member being provided with stop means for engaging said projection on said second'ring when the diaphragm adjusting ring is rotated in a direction in which the aperture of the diaphragm is reduced, whereby the reduction in the size pf the diaphragm aperture is limited'to the size represented by the selected position in which said second ring is locked tosaid diaphragm adjusting ring.

3. In 'an adjustable graphic objectives,

4 adjusting ring, a second ring within said diaphragm adjusting ring and independently rotatable with respect to the latter, manually controlled means i'or locking said second ring selectively in `a series of positions to said diaphragm adjusting ring, said manually controlled means including a resilient strip attached with one end to said second ring and resiliently engaging said diaphragm adjusting ring with its other end, said last named end of the strip being adapted to engage seletively any one of a series of notches provided in said diaphragm adjusting ring, and on said last named strip from any one o! said notches, notches representing a difierent predetermined diaphragm aperture, a projection on said second ring, and a stationary member on which said second ring is rotatably mounted, said stationary member being provided with stop means for engaging said projection on said second ring when' the diaphragm adjusting ring is rotated in a direction in which the aperture of the diaphragm is reduced, whereby the reduction in the size of the diaphragm aperture is limited to the size represented by the selected position in which said Second ring is locked to said diaphragm adjusting ring.

HUBERT NERWIN. 

